Download ISP205 Spring 2001 Exam #1 Study Guide

ISP205 Spring 2001 Exam #1 Study Guide: This guide is intended to highlight the important material you should
know for the first exam. Warning: there may be material on the exam from chapters 1-5 that is not listed here. The
exam will not cover identifying stars or constellations.
I.
II.
Preface:
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B.
C.
Chpt 1:
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B.
C.
D.
III.
Chpt 2:
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B.
C.
IV.
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E.
Chpt 3:
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B.
C.
D.
E.
F.
G.
H.
Scientific notation.
What is a constellation?
What is a light year? How big is a light year? Speed of light in vacuum: 3x105 m/s
Know the definition of the celestial sphere and the meaning of
1. celestial equator - projection of the Earth’s equator
2. celestial north and south pole - projection of the Earth’s north pole
3. ecliptic - apparent path of the sun through the fixed stars. The planets lie mostly along the
ecliptic. The constellations of the zodiac also lie along the ecliptic.
4. precession - the change in the location of the celestial north pole (26,000 year period).
Know the difference between Geocentric - Earth centered - and Heliocentric - Sun centered models
of the solar system.
Ptolemy devised a successful Earth centered model based on circles and epicycles. Why was the
Ptolemy’s system accepted? It worked pretty well.
Contributions of Galileo: Sun spots, Moons orbit Jupiter, Phases of Venus, Mountains on the
Moon, Studied motion
Brahe - made detailed measurements that allowed Kepler to deduce planetary motion
Kepler - know his three laws and their meaning
1. Orbits are ellipses
2. Equal areas in equal times (the planet moves faster when closer to the Sun)
3. D2=T3
Newton
1. know his three force laws and what they mean for astronomy
2. know how universal law of gravity depends on mass and distance. Be able to answer
various questions: What happens to gravity if the mass of the Earth is increased? It is
stronger. How much does gravity change if the radius of the Earth is doubled, but the
mass is kept the same? It is 4 times less.
3. Newton's version of Kepler's third law is a way to measure mass.
Why are astronauts weightless in orbit?
Which falls faster on the Moon, a hammer or a feather?
Measurement of angles: degrees, minutes of arc, seconds of arc
Angular size (same as apparent size). It is size/distance.
1. Know how to use your hand to estimate angular size
a.
What angle for an open hand
b.
What angle for closed hand
c.
What angle for a thumb’s width
2. What are the apparent sizes of the Sun and Moon?
Know the difference between a solar day and a sidereal day. A solar day is 3.9 minutes longer.
How far does the Sun move with respect to the fixed stars in one day? (Answer: 360° /365days = 1
degree). The apparent motion is eastward. Why?
Know the coordinates on the celestial sphere.
1. Right Ascension – equivalent of longitude
a.
Know this is measured in hours? Why?
b.
Where is 0h?
c.
How many degrees is 1h? (360/24 = 15 degrees)
2. Declination – equivalent of latitude
a.
What is the declination of the North Star?
b.
What is the approximate declination of the stars in Orion’s Belt?
Seasons on the Earth
1. Know the definitions of: equinoxes, summer solstice and winter solstice.
2. What are the reasons for the seasons?
Phases of the moon
1. What causes the phases of the moon?
2. Know when the various phases rise, set, and are highest in the sky.
Solar and Lunar eclipses
1.
2.
V.
Chpt. 4
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
I.
When do eclipses occur?
Why don’t they happen every month?
Know the three main characteristics of waves:
1. Amplitude
2. Wavelength, λ
3. Period (frequency = 1/ period and is measured in Hz)
What is the relationship between wave speed, wavelength and frequency (speed = wavelength times
frequency).
Electromagnetic Radiation:
1. Know what it is.
2. What are the parts of the EM spectrum? radio, TV (VHF/UHF), microwaves, infrared,
visible, ultraviolet, X-rays, gamma rays.
3. What is the range of visible light? 400-700 nanometers
4. Which photons have higher energy? Higher frequency? Longer wavelength?
5. What parts can get through the Earth’s atmosphere? Visible and Microwave
Know the relationship between Energy, wavelength and frequency.
1. Higher energy means higher frequency
2. Higher energy means shorter wavelength
3. Higher frequency means shorter wavelength
What are the three kinds of spectra? Continuous, Emission (bright-line), and Absorption (darkline).
Continuous spectra
1. Know the source of this kind of spectra.
2. Determined by the temperature. Hotter means more blue and brighter.
3. Know the temperature dependence of the peak wavelength and total power (watts)
output. Depends on the surface area and the fourth power of the temperature.
Emission line (bright line) spectra
1. Know the source of this kind of spectra
2. Know that this gives a fingerprint of chemical elements.
Absorption (dark-line) spectra
1. Know how this kind of spectrum is formed.
2. Know how a continuous spectrum is turned into a dark-line spectrum?
3. Know this give a fingerprint of the chemical elements there.
Know about the atomic energy level diagram and the various parts (what is a ground state, what are
excited states, what is a transition). In a transition a photon of the transition energy is given off.
What is the Doppler effect?
1. Motion toward means a higher frequency (more blue)
2. Motion away means a lower frequency (more red)
Chpt 5
A.
B.
C.
D.
E.
Know the major components of a telescope: Objective (primary) lens or mirror (determines the
aperture of the telescope) + eyepiece
Types of telescopes:
1. Reflector
a. Uses a mirror for the primary
b. Does not suffer from chromatic aberrations
c. Used in all modern large telescopes
2. Refractors
a. Uses a large lens as the primary
b. Has chromatic aberration
Know the three properties the objective determines:
1. light gathering power, depends on the area of the aperture, D2
2. resolving power, gets better for larger aperture, but is limited to around 1 arcsec by
“seeing”
3. magnification (objective focal length/eyepiece focal length)
What is seeing? What limit does it make on astronomical measurements?
Why are detectors important? Reduced reliance on human perception and can integrate photons
over a longer time